[Serusers] session timers

Hi All, I have the following question: I would like to know if there is an extension and/or and RFC related with timer sessions. The idea is to use timer sessions in final users, in order to shut down sessions at pre-defined times (at the begining of them) without necessity of deal with timer at servers (no necessity of dialog statefull servers). As far as I know, there is draft, "Session Timers in the Session Initiation Protocol (SIP)", draft-ietf-sip-session-timer-15 (july 2004), which is already implemented by some companies like Addpac. But, it is not directly applicable to our necessity (it is just a mechanism of keep-alive). Thanks in advance! Jorge